Fusing machines have been in existence for many years. In Warner U.S. Pat. No. 3,045,103, there is disclosed a fusing machine which has been marketed successfully for a number of years by the assignee of the present invention. Despite the commercial success of the fusing machine of the Warner patent, the machine has room for improvement. For instance, the prior fusing machine employs a fusing electrode assembly, including a fusing electrode shaft and a pair of counteracting springs, i.e., a weld following spring for pressing a fusing electrode into contact with a workpiece and a return spring for moving the fusing electrode out of contact with the workpiece. Because the return spring acts against the weld following spring, it is difficult to properly compress the weld following spring, making it difficult to achieve consistent welds. The weld following spring is also difficult to replace, thereby increasing machine down time during spring changing operations.
The fusing electrode assembly also utilizes a reciprocating guide pin and a reciprocating stop shaft, both of which are arranged parallel to the fusing electrode shaft. Because of such a parallel arrangement, the fusing electrode shaft can pivot relative to the guide pin and the stop shaft and, therefore, become jammed during its reciprocating movement in a bearing bracket.
In the prior fusing machine, the fusing electrode is simply clamped between a pair of jaws attached to the fusing electrode shaft. Because the jaws are only held together by screws, the jaws can move laterally relative to each other, resulting in an undesired lateral movement of the fusing electrode. The lateral movement of the fusing electrode complicates its proper alignment and positioning.
The fusing electrode assembly is mounted to a main frame, including a bed attached to the main frame. The bed carries an armature-commutator holding and indexing mechanism. The bed is adjustable so that its position can be varied to compensate for various sized commutators. Because the position of the armature-commutator holding and indexing mechanism changes in response to the movement of the bed, different sized commutators must be fed to the armature-commutator holding and indexing mechanism at different elevations, thereby complicating feeding operations. If all of the commutators are fed at the same elevation, then fusing operations must be periodically interrupted to adjust the position of the bed and, hence, the armature-commutator holding and indexing mechanism in order to receive different sized commutators and properly position them relative to the fusing electrode and a ground electrode.